* {
    margin: 0px;
    padding: 0px;
}

html,
body {
    height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
}

.calc_wrap {
    background-color: gray;
    border-radius: 10px;
    width: 500px;
    height: 400px;
    padding: 20px;
    display: flex;
    flex-direction: column;

}

.screen {
    height: 100px;
    background-color: white;
    border-radius: 10px;
}

.operation_area {
    margin-top: 20px;
    flex: 1;
    height: 0;
    display: grid;
    gap: 10px;
    grid-template-columns: repeat(5, 1fr);
    grid-template-rows: repeat(4, 1fr);
}

.btn {
    background-color: white;
    display: flex;
    justify-content: center;
    align-items: center;
    font-weight: bolder;
    font-size: 200%;
    border-radius: 10px;
    cursor: pointer;
}

.btn_clear {

    background-color: red;
}


.btn_equal {
    grid-row: span 3;
    background-color: yellow;
}

.btn_zero {

    grid-column: span 2;
}

.screen {
    display: flex;
    justify-content: end;
    align-items: center;
    font-weight: bolder;
    font-size: 200%;
    padding: 10px;
}